>>1353319That's ezpz for 25s so long as you stick to the ruts. The loose stuff might be a bit sketch.
>>1353320HIIT's effectiveness in is science science, stemming from Tabata. Here's a pretty extensive article covering the studies that have been done on various forms of HIIT
http://fellrnr.com/wiki/The_Science_of_High_Intensity_Interval_TrainingHRM is not necessary but useful for establishing where your max effort is so that you know what 90% max is,, and can work in concert with various training apps. There are different varieties for different goals, like descending intervals (a.k.a. miracle intervals) for burning fat. They suck but being slow sucks more.
